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Author Topic: Notes about repairing old 80xx handheld Fluke meters  (Read 4209 times)

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Offline Excavatoree

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Notes about repairing old 80xx handheld Fluke meters
« on: August 19, 2013, 12:23:16 pm »
After learning about the capacitor problem in old fluke 80xx handheld meters, I decided to see if any of the meters in my "dead 80xx" box could be repaired.  Many of them had so much corrosion that they were too far gone - repairable, but considering I don't have enough LCDs, switch assys, and unbroken cases, they aren't worth the trouble.

What interested me is that some of them did not have the "tin can" aluminum electrolytic capacitors, but instead had what looked to be tantalum capacitors.   Stranger, these were the older "A" series. (8020A,  8024A)  I did have one 8020B with a tantalum, but I'm not sure if it wasn't a 8020A in a 8020B case.  These are some crusty meters, some of the lots I bought were obviously not all original.

Has anyone heard of Fluke doing this?  Did they start with tantalum, then go to aluminum as a cost cutting measure?  Was it a factory fix?

« Last Edit: November 26, 2013, 02:37:23 pm by Excavatoree »
 

Offline Excavatoree

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RE:Notes about repairing old 80xx handheld Fluke meters
« Reply #1 on: August 20, 2013, 02:38:08 pm »
I noticed that of all my meters in the pile, the only capacitors that didn't leak were either Nichicon or Nippon Chemi-Con.  (perhaps the US subsidiary, United Chemi-Con)  The leaky capacitors were Matshshita (old triangle logo) or unbranded.  The boards were all from 1980 or 1981.

Thanks to Modemhead and Retiredcaps for their help.




« Last Edit: August 27, 2013, 06:11:52 pm by Excavatoree »
 

Offline Excavatoree

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Re: Notes about repairing old 80xx handheld Fluke meters
« Reply #2 on: August 27, 2013, 06:15:38 pm »
I changed the thread title so I could add other items as I find them.

I purchased three additional meters (that I need like a hole in my head) because they were consecutive serial numbers. 

I didn't pay too much attention to a line in the seller's description "powered up with external adaptor (not included)"  until I noticed that the meter would not power on with a battery.  Sure enough, the DC jack was bad - the internal switch that disconnects the battery when external power is applied was defective. 

I wonder if the jack was bad, or if the seller damaged it by inserting an incorrect adaptor?

In any case, I have found some New Old Stock jacks from a parts seller, or I may just cannibalize other meters I have.

It's something to check when one has a "dead" 80xx handheld.

« Last Edit: August 27, 2013, 07:30:59 pm by Excavatoree »
 

Offline retiredcaps

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Re: Notes about repairing old 80xx handheld Fluke meters
« Reply #3 on: August 28, 2013, 05:35:21 am »
Has anyone heard of Fluke doing this?  Did they start with tantalum, then go to aluminum as a cost cutting measure?  Was it a factory fix?
I have noticed that Fluke, like any manufacturer, routinely updates their pcb with changes over time.  We have evidence of that with the Fluke 87V GSM fix, the Fluke 17B as shown in Martin's videos, and a Fluke 175 that modemhead recently acquired.

So it wouldn't surprise me if Fluke changed components on their BOM for whatever reason.  While they may have documented the procedure internally, I doubt they would release a revised schematic/BOM to the general user population.

The IBM 8060A user manual that I have clearly lists electrolytic capacitors.  It is possible that earlier/later revisions to the pcb added or removed the electrolytic capacitors.

In my industry, the term "value engineering" is thrown around to mean subsequent revisions are generally firmware fixes and cost reduction.
 

Offline Excavatoree

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Re: Notes about repairing old 80xx handheld Fluke meters
« Reply #4 on: August 28, 2013, 12:44:32 pm »
I checked the other two "consecutive" units, and was surprised again.  After the first mechanically defective power jack, I thought the other two dead units had the same problem.

Their power jacks were fine.  However, the 12V zener protection diode, across the battery (and DC in,) was blown on both units.  These three units  could possibly be the victims of someone who didn't have the correct power adaptor.

Fortunately, their capacitors are good.    The only problem is one has an lCD with a black blob at all four edges.  It seems that LCDs are my limiting factor as to how many of my "junk pile" units I'll be able to get working.
« Last Edit: August 28, 2013, 06:55:39 pm by Excavatoree »
 

Offline ModemHead

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Re: Notes about repairing old 80xx handheld Fluke meters
« Reply #5 on: August 28, 2013, 12:45:25 pm »
Has anyone heard of Fluke doing this?  Did they start with tantalum, then go to aluminum as a cost cutting measure?  Was it a factory fix?
I only have one each of an 8020A, 8020B, 8062A, and 8060A. Statistically meaningless, but all the >= 1uF caps in these units are aluminum cans.  With one notable exception, the 1uF/35V auto-zero cap in both the 8062A and 8060A is a dipped tantalum. The low leakage was desirable in this spot, presumably.

Given the propensity for these caps to fail short, maybe Fluke decided the cans were more reliable?  Most of the larger-valued caps are across power rails and such.  Of course, now at 30+ years old we know what sort of damage the electrolytics can do too.
 

Offline Excavatoree

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Re: Notes about repairing old 80xx handheld Fluke meters
« Reply #6 on: December 01, 2013, 07:22:12 pm »
I purchased an 8026 (still in the box, which was obviously in someone's shop for a long time - the seller included some green spray paint overspray on one side)which appears to be an 8020 with the true RMS IC installed.

Learning from those here that know these things better than I, I replaced the capacitors first thing - even before a complete check.   After replacing them, I checked the meter and found both AC and DC voltage readings to be good.  The resistance was terrible.  1 ohm read as 4 ohms, 10 ohms read as 15, and so on.  The manual suggested the Z1 resistor assy.  I removed it, and found some adhesive residue from a piece of orange foam that someone had added to keep the continuity beeper board stabilized.  I'm not sure if this was someone's addition or if this is from the Fluke factory.  I cleaned the adhesive off, and re-installed to find the problem was corrected.

I wouldn't think that would be it, but I can't think of any other explanation - all the solder connections were good before I removed it.

Does anyone know if the orange foam was placed there by Fluke?
 


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